Oil burner assemblies



April 25, 1967 E. A. ROESKE 3,315,604

OIL BURNER ASSEMBLIES Filed March 29, 1965 2 Sheets-Sheet 1 April 1967E. A. ROESKE 3,315,604

2 Sheet eeeeee t 2 W UHF WI" United States Patent 3,315,604 OIL BURNERASSEMBLIES Eugene A. Roeske, St. Louis, Mo., assignor to EmersonElectric Co., St. Louis, Mo., a corporation of Missouri Filed Mar. 29,1965, Ser. No. 443,441 2 Claims. (Cl. 103-6) This invention rel-ates tooil burners of the type in which a combustible mixture of air and oil isintroduced into a furnace. It relates particularly to that part of anoil burner assembly which supplies the air and oil to the systemimmediately before the oil and air are introduced into the furnace.

In oil burners commonly used commercially, it is customary to provide acentrally located blower, with a blower housing, outside and at one sideof which is an electric motor and outside and at the other side of whichis an oil pump. A blower wheel inside the housing, is mounted on themotor shaft, which extends through the housing. The motor is eitherfully enclosed, or is provided with a fire pan extending beneath it. Themotor shaft is coupled by means of a long coupling to the shaft of theoil pump.

This arrangement requires a considerable space, and the use of at leastfour bearings in the usual arrangement. One of the objects of thisinvention is to provide an oil burner assembly which is more compactthan assemblies known heretofore, and at the same time is moreefficient.

Another object is to provide an oil burner assembly in which the heatgenerated within the electric motor is utilized to improve theefliciency of the oil burner and at least some of its components.

Other objects will become apparent to those skilled in the "art in thelight of the following description and accompanying drawing.

In accordance with this invention, generally stated, an oil burnerassembly is provided, which includes an electric motor having a woundstator and a motor housing in heat transfer relation with the woundstator. An oil chamber is defined within the housing in heat transferrelation therewith, and fuel oil to be supplied immediately to thefurnace is passed through the oil chamber to pick up the heat from thewound stator prior to the oils being introduced to the furnace. Thisarrangement not only permits the oil to be preheated, but it improvesthe efficiency of the atomization and combustion of the oil, and it alsohas the effect of dissipating the heat from the motor, so that a smallermotor can be used than could otherwise be used for the purpose.

The wound stator is mounted within the blower housing itself, and ablower wheel, connected to be driven by the motor shaft, is providedwith blades which encompass the wound stator, within a passage definedbetween the stator and the blower housing. The blower housing iscontinuous along the under side of the motor, so as to form a fire panfor those embodiments of the assembly in which open motors are used. Theblower housing is open at one end to admit air, and is provided with adischarge opening so located that the air drawn through the inletopenings by the blower, passes in heat transfer relation to the woundstator as it moves through the passage between the stator and the blowerhousing, so as to be preheated before it reaches the furnace, and todissipate heat from the wound stator.

The motor housing includes an end shield which carries a bearing inwhich a rotor shaft (the motor shaft) is journalled. In one embodimentshown and described, the end shield is provided with an elongatedpassage which serves as the oil chamber. In another embodiment, the endshield serves as one closure member of a totally enclosing motorhousing, the interior of which serves as the oil chamber so that fueloil introduced to the oil cham- 3,315,604 Patented Apr. 25, 1967 her isin direct contact with the windings of the wound stator.

In the prefer-red embodiment, the means for introducing to the furnacethe oil component of the flammable mixture includes a gear pump of theinternally toothed type, having a suction and a discharge side. Thesuction side of the pump is connected to communicate with the oilchamber. In such a pump, an internally toothed gear is journalled withina pump housing, which, in the preferred embodiment, is an integral partof the end shield. In this embodiment, the pump is closed by a pumphousing cover, which also contains a valving device and fittings forconnections to a fuel oil conduit to a nozzle in the furnace and to asource of fuel oil. A manifold with suction and discharge manifold partsmay be provided in the cover or in the end shield, or both dependingupon the embodiment.

While the gear pump type of burner assembly is preferred, for reasons ofsimplicity, efficiency, and compactness, many of the features of thisinvention are applicable to other types of oil introducing devices, suchas eductors e.g. so-called low pressure systems.

In the drawing:

FIGURE 1 is a sectional view of one embodiment of oil burner assemblyconstructed in accordance with this invention;

'FIGURE 2 is a sectional View taken along the line 22 of FIG. 1;

FIGURE 3 is a sectional view taken along the line 3 3 of FIG. 1; and

FIGURE 4 is a sectional view showing still another embodiment of oilburner assembly of this invention.

Referring now to the drawing, and particularly to FIGS. 1, 2 and 3 forone illustrative embodiment of oil burner assembly of this invention,reference numeral 1 indicates an oil burner equipped with an assembly ofthis invention. The oil burner 1 includes a furnace plate 2, atransformer 3 which forms part of the conventional ignition system, anair duct 4, an oil discharge conduit 5, which termimates in a spraynozzle, not here shown, and an assembly 10.

The furnace plate 2, transformer 3, air duct 4 and oil discharge tube 5are all standard commercial components, and, as such, form no part ofthis invention.

The assembly 10 includes a motor 20, a blower assembly 60, 'a pump 80,and a valve assembly 90.

The motor 20, in this embodiment, includes a heavy end shield 21, an endbell 22, a wound stator 23, a rotor 24 and a rotor shaft 25. The endshield 21 and end bell 22 together form a motor housing 30. The rotorshaft 25 is journalled, at one side of the rotor 24, in a bearing 26 ina hub section 27 of the end shield 21, and on the other side of therotor, in a bearing 28 in a boss 29 on the end bell 22. The end bell 22is deep, and is provided with an inner shoulder 31 against which alaminated core 35 of the stator 23 rests to locate the stator withrespect to the motor housing 30. The end bell 22 has an exterior rabbetat its open end, which mates with a flange on the end shield 21, andforms, with the aid of an O-ring 33, an oil tight oil chamber 37.Windings 36, extending within slots in the core 35 and having end turnsprojecting at each end from the core 35, are exposed within the oilchamber 37. Pins 38, on either side of the core 35, serve to hold backthe end turns of the windings 36, so that they will not interfere withend rings 39 of the rotor 24. The end ring 39 adjacent the hub 27, inthe embodiment shown, has formed in its blade 40, which help circulatethe oil in the oil chamber 37.

A passage 42 in the boss 29 of the end bell 22 leads between the bearing28 and a gland 43, to permit oil to lubricate the outer end of thebearing 28. An oil supply passage 41 in the hub 27 of the end shield 21communi- I its outer periphery.

A screen 49 is positioned within the compass of the end bell 22, withone, inner margin of the screen bearing against the boss 29, and anouter margin bearing against a radial surface of the stator core 35. Apassage 51, extends through the stator core 35, communicating at one endwith the oil passage 46, and its other, with a part of the oil chamber37 between the end bell 22 and the screen The motor 20 is mounted onand'largely within a blower housing 61. The blower housing 61 includesside walls 62 and 63, and a scroll-defining web 64. The web 64isimperforate, and forms an enclosure constituting a fire pan around thelower part of the motor 20. The wall 63 has a motor-receiving opening,within which end shield 21 is seated with the flange 48 in engagementwith the opening-defining margin of the wall 63, as shown in FIG- URE l.The motor is held in position by any suitable means not here shown,whichmay take the form of bolts and spring-nuts such as is illustratedin connection with the embodiment shown in FIGURE 4. The wall 62 isprovided with a multiplicity of radially extending wedge shaped openings64 and a damper plate 65, mounted on the wall 61 by means of a bolt 66,

, is provided with similar holes 67, which, upon selective rotation ofthe plate 65, are either aligned with the openings 64' to provideunhindered ingress of air,'or offset with respect to the openings 64 soas to throttle the ingress of air. The upper part of the housing 61communicates with the air duct 4.

Within the housing 61 a blower wheel 70 is mounted, by means of a hub71, on one end of the rotor shaft 25.

The blower wheel includes a spider 72, welded to the hub 71' at one endand integral at its otherend with a rim 73, blades'75, integral at oneend with the rim 73 and at the other end with an outer rim 76. As isreadily apparent from FIGURE 1, the blades 75 embrace the motor housing30, and revolve within a passage 78 defined between the motor housing30and the web 64 of the blower housing 61. w a

The pump 80 includes the manifold port 45 formed in the end shield'hub27, a discharge balancing manifold 81, also formed in the hub 27, anexternally toothed gear 82,

, keyed toone end of the shaft 25, an internally toothed gear 83, andapump housing 84, integral with the hub 27,

.in which the internally toothed gear 83 is journalled for rotation. AnO-ring 85, seated in an annular groove 86 in a flat 87 on the face ofthe end shield 21, serves to seal a the pump, when a flat face of acover plate 92 made integral with a casing 95, of the valve assembly 90,is fastened to the end shield 21 by means of studs 96. V The I coverplate 91 has in it two manifold ports, a suction balancing manifold port93 and a discharge manifold port 94. The suctionbalancing manifold port93 communicates with the suction side of the pump 80' at one end, and atitsother end with a valve bore 97 on one side of valve piston 98slideably mounted in the bore 97. The discharge manifold port 94communicates at one end with the discharge, side of the pump 80, and :atits other end, with the valve bore 97 on the other side, axially, of thevalve piston 98. The, valve piston 98 has, on the discharge side,

- a valve stem 99 with a conical head 100, which seats against a valveseat 101 in a fitting 102, threadedlymounted in the valve casing 95. Thefitting 102 has an axially directed passage 103, communicating at oneend with a passage in the valve seat 101, and at its other, with the,oil discharge conduit 5. On the suction side of the.

valve piston 98, the piston is provided with a spring boss 105, whichpositions a helical spring 106. The helical spring 106 bears at one endon the under side of the valve piston 98, and, at its other end, on astop washer 107. Stop washer 107 bears against an end of an adjustingscrew 108, which is threaded into the lower end of the casing 95 inaxial alignment with the bore 97 The adjusting screw 108 is held inposition by nuts 109.

On the discharge side of valve piston 98, a gauge fitting socket 112 isprovided. The socket 112 is normally I plugged, although a pressuregauge can be mounted perma- The valve assembly 1s provided with ibypasspassages so exceeds a predeterthat when the pressure from the pump thefuel oil is mined limit by the setting of spring 106,

V bypassed, either back to the oil supply conduit or tank, or

to the suction side of the pump, the system. This, however, 'is standardin hydraulic systems, and is not here illustrated. a

In the operation of the assembly illustrated in this embodiment,assuming that the openings 64' and 67 have been adjusted so as to admitthe desired amount of air, that the socket 112 is closed either by aplug or gauge, that the adjusting screw 108 has been adjusted to providethe amount of compression of the helical spring 106 required to give thedesired flow of oil, and that, by virtue of the elevation of the oilsupply tank, the motor housing, i.e. the oil chamber 37, is filled withfuel oil. When the motor is energized from a source of alternatingcurrent,

not here shown, the stator windings immediately begin to heat, even asthe motor is starting. The rotor 24 begins 7 to rotate, turning theexternally toothed gear 82 and the internally toothed gear 83, to beginpumping fuel oil from the oil chamber 37, in through the pa'ssage41 andsuction manifold port 45 and out through the dischargemanifold' intimatecontact with the windings 36 themselves, and-the rotation of the rotor24 insures a vigorous circulation of the fuel oil within the oil chamber37. The rotation of the rotor 24 also causes rotation of the blowerwheel 70, whereby around themotor casing 30. direct'heat transferrelation with the stator core 35, and

in heat transfer relation by radiation, convection and conductionthrough the fuel oil with the windings 36. The casing 30, accordingly,heats sensibly, and, in turn, heats the air which is drawn through theopenings 64 into'the 1 7 fan wheel 70, over the casing,.and out throughthe blades 75 to the duct 4, hence into. the furnace. The heating of thefuel oil by the stator windings before the oil is delivered to thefurnace, and. the heating o' f the air not only improve the eificiencyof the atomizing and efliciency of the burning of the fueloil, butalsoserve to cool the motor 20; It is also to be noted that intheconstruction of this embodiment of oil burner assembly, only twobearings are required,--no couplings between shafts, and

only half orless of the space occupied by .the conventional'oilbnrnerassembly. a e

Referring now to FIG. 4' for another embodiment of oil burner assemblyof this invention'reference numeral indicates the assembly part of anoil burner. Theassembly 110 is incorporated 'into an oil burner of thesame type as that shown in FIG. 1. The assembly 110 includes a motor120, a blower160, a pump and a valve assembly 190. I

The motor 120, in this embodiment, includes an outer end shield 121, aninner end shield 122, a stator housing 133, 'a wound stator 123, a rotor124, and a rotor shaft 125. The outer and inner end shields arerabbetedito so as to prevent injury to comes through the passage51 inthe stator core 35,

the blades 75a're driven The motor casing 30 isin) receive the statorhousing 133, and held together by through-bolts 134, in this respectbeing conventional. The inner end shield 122 carries a conventionalbearing assembly 126, which includes felt oil rings 128. A lubricatingoil passage 129 extends radially through the inner end shield 122, andcommunicateswith the hearing assembly 126, so that the bearing assemblycan be oiled.

The rotor shaft 125 is journalled at one end in a sleeve bearing in thebearing assembly 126, and projects through and beyond the inner endshield 122, to carry a blower assembly 170 which is identical in everyrespect with the blower assembly 70 of the embodiment shown in FIG. 1.

The motor 120 is mounted on and in part within the blower housing bymeans of bolts 135 extending through holes in the end shield 121 andcorresponding holes in the blower housing, and spring nuts 136.

The outer end shield 121 has a heavy hub section 127. The hub 127carries a bearing 130, in which the other end of the rotor shaft 125 isjournalled and through and beyond which it extends. A gland drainpassage 137 extends through the hub 127 from a sealing gland 138 to thesuction side of the pump 180. The hub 127 is provided with a relativelylarge annular channel 131, concentric with the bearing 130 and spacedradially outwardly from and extending around a pump housing 184,integral with the hub 127. An accordian-folded screen 139 is seated inthe channel 131. Radially outboard of the channel 131 is an annulargroove 132, in which an O-ring is seated. The groove 132, channel 131,and pump housing 184 all open through a flat face 144 of the hub 127,and are all closed by a complementary face 191 of a housing 192 which ispart of the valve assembly 190. The housing 192 is bolted to the face ofthe hub 127 of the outer end shield 121 by means of studs, not hereshown, but which may be similar to the studs 96 of the embodiment shownin FIGS. 1 and 2.

The pump 180 of this embodiment is substantially identical with the pump80 of the embodiment shown in FIGS. 1-3. It includes a suction manifoldport 145 formed in the end shield hub 127, a distance balancing manifold181, also formed in the hub 27, an auxiliary suction manifold port 193in the valve housing 192, and a discharge manifold port 194, also in thevalve housing 192. An externally toothed gear is keyed to the end of theshaft 125, within the housing 184, and an internally toothed gear isjournalled in the housing 184, exactly as the gears 82 and 83 shown inFIGS. 1 and 2.

A fuel oil suction passage 141 communicates at one end with the suctionmonifold port 145, and at its other, with the channel 131, which, closedby the cover of valve housing 192, constitutes an oil chamber for thereception of fuel oil. Au internally threaded fitting socket 147 isprovided in the valve housing 192, which socket communicates, through apassage 146, with the chamber 131. As in the other embodiment, thesocket 147 receives an externally threaded fitting on a fuel oil supplyconduit communicating with a source of fuel oil, not here shown.

While there are some light differences in configuration of the parts,notably the valve seat and the valve head, the construction andarrangement of the valving parts of the valve assembly 190 areessentially the same as those of the embodiment shown in FIG. 1.

It can be seen that in the embodiment shown in FIG. 4, the hub 127 is inheat transfer relation to the windings of the stator 123, and the fueloil, instead of circulating within the motor housing, circulates,through the screen within the chamber 131, where it picks up heat fromthe windings.

The operation of the oil burner assembly shown in FIG. 4 issubstantially the same as that of the embodiment shown in FIGS. 1-3. Ifthe amount of heat absorbed by the fuel oil in the chamber 131 issomewhat less than the amount absorbed by the fuel oil within thechamber defined by the motor housing itself in the first embodiment, theair, in the second embodiment, will be heated the more, and the greatertemperature gradient between the initial temperature of the air and thetemperature of the motor will promote greater heat transfer, hencegreater cooling of the motor by the air and greater heating of the airby the motor than is accomplished by the embodiment shown in FIG. 1.

Numerous variations in the construction of the oil burner assembly ofthis invention, within the scope of the appended claims, will occur tothose skilled in the art in the light of the foregoing disclosure.Merely by way of example, various other types of blower construction,pump construction and valve construction can be used; the burner itselfcan be of the low pressure, eduction type, in which a pump of the geartype plays a lesser and perhaps nonexistent role, but in which,nevertheless, the fuel oil can be drawn through a fuel oil chamber inheat-transfer relation to the windings of the motor; or a single bearingmotor might be utilized. These are, as has been indicated, merelyillustrative of variations which will occur spontaneously to thoseskilled in the art in the light of the foregoing disclosure.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. An oil burner assembly comprising an electric motor having a woundstator, a rotor including a rotor shaft, 21 motor housing including anend shield in heat transfer relation to the wound stator, a pump havingan impeller, a pump housing, and suction and discharge manifold ports insaid housing, a major portion of said pump housing being integral withsaid end shield, said impeller being connected to be driven by saidrotor shaft, said motor housing having an oil chamber within it, in heattransfer relation to said wound stator, whereby fuel oil in said chamberis heated by said wound stator when the motor is in operation, saidchamber communicating with one of said manifold ports, a blower housingencompassing the said motor and spaced radially from said wound statorto define therewith a passage, and a blower wheel mounted to embracesaid wound stator, connected to be driven by said rotor shaft, andarranged to blow air through said passage.

2. An oil burner assembly comprising an electric motor having a woundstator,- a rotor including a rotor shaft, a motor housing inheat'transfer relation with the said wound stator, an oil pump having apumping part connected to said rotor shaft and suction and dischargemanifold ports, an oil chamber defined within said housing in heattransfer relation therewith, whereby fuel oil in said chamber is heatedby said wound stator when the motor is in operation, said chambercommunicating with one of said manifold ports, a blower housingencompassing the said motor and spaced radially from said Wound statorto define therewith a passage, and a blower wheel mounted to embracesaid wound stator, connected to be driven by said rotor shaft, andarranged to blow air through said passage.

References Cited by the Examiner UNITED STATES PATENTS 1,057,282 3/1913Schaeffer 230l 17 2,494,714 1/1950 Lyman 1036 X 2,658,567 11/1953VVitherell 158-363 X 2,776,385 1/1957 Modrey.

2,885,962 5/1959 Campbell l03118 X 3,220,461 11/1965 Richardson 158 -363FREDERICK KETTERER, Primary Examiner.

1. AN OIL BURNER ASSEMBLY COMPRISING AN ELECTRIC MOTOR HAVING A WOUNDSTATOR, A ROTOR INCLUDING A ROTOR SHAFT, A MOTOR HOUSING INCLUDING ANEND SHIELD IN HEAT TRANSFER RELATION TO THE WOUND STATOR, A PUMP HAVINGAN IMPELLER, A PUMP HOUSING, AND SUCTION AND DISCHARGE MANIFORD PORTS INSAID HOUSING, A MAJOR PORTION OF SAID PUMP HOUSING BEING INTEGRAL WITHSAID END SHIELD, SAID IMPELLER BEING CONNECTED TO BE DRIVEN BY SAIDROTOR SHAFT, SAID MOTOR HOUSING HAVING AN OIL CHAMBER WITHIN IT, IN HEATTRANSFER RELATION TO SAID WOUND STATOR, WHEREBY FUEL OIL IN SAID CHAMBERIS HEATED BY SAID WOUND STATOR WHEN THE MOTOR IS IN OPERATION, SAIDCHAMBER COMMUNICATING WITH ONE OF SAID MANIFOLD PORTS, A BLOWER HOUSINGENCOMPASSING THE SAID MOTOR AND SPACED RADIALLY FROM SAID WOUND STATORTO DEFINE THEREWITH A PASSAGE, AND A BLOWER WHEEL MOUNTED TO EMBRACESAID WOUND STATOR, CONNECTED TO BE DRIVEN BY SAID ROTOR SHAFT, ANDARRANGED TO BLOW AIR THROUGH SAID PASSAGE.